The use of machine based vision systems has always been a computationally intensive task as a large number of pixels need to be processed in order for the acquired image to be processed. This processing requirement arises from the need for high resolution images to be acquired to accurately represent the item represented in the image. The processing capabilities of embedded processing systems that are part of machine based vision systems have required the lowest possible image resolution images to be used.
Previous solutions have either used large and expensive processing systems if the vision systems are required to operate in near-real time or used an off-line processing approach that would not permit the determination of vision based decisions before the next item is examined by the vision system. Off-line systems are not useful in most applications as automating the visual inspection of items typically is desired for a large number of items, such as a sequence of items found on an assembly line.
Typically, an item being inspected will possess a range of image resolution values that may be successfully used in vision systems. The minimum resolution that may be used for the processing to be performed in the vision processing system will depend upon the information content found within a reference image that is compared with acquired images. In order for a vision system to minimize the processing requirements of the vision system, a range of acceptable resolution values needs to be determined. In prior systems, no such range of acceptable image resolution values have been determined. The present invention disclosed herein overcomes the above limitations of the prior art machine-based vision systems.